1. Technical Field
The present invention relates to a structure for transmitting data at a rotor of a three-dimensional position-measuring apparatus.
2. Background Art
A three-dimensional position-measuring apparatus using a laser beam is known (for example, see Japanese Unexamined Patent Application Publication (translation of PCT Application) No. 2000-509150). The three-dimensional position-measuring apparatus scans and measures a position in a three-dimensional space using a distance-measuring device using a laser beam. Since the laser beam should be used to scan in three dimensions and should be irradiated on the surroundings, a three-dimensional position-measuring apparatus comprises a measuring portion which is rotatable with respect to a body and functions as an irradiating portion and a light receiving portion for the laser beam, as disclosed in Japanese Unexamined Patent Application (translation of PCT Application) No. 2000-509150.
Thus, the measuring portion is required to rotate with respect to the body and requires electrical power, which is supplied from the body, and various signals are transmitted between the measuring portion and the body. Therefore, the body and the measuring portion are disposed with electrodes at a concentric circumferential position with respect to the rotational axis, whereby electrical contact is ensured between the electrodes corresponding to each other when the measuring portion rotates with respect to the body.
However, since electrical contact between the body and the measuring portion that rotate with respect to each other is ensured by the above-described mechanical contact, the contact may become worn, and the durability thereof is low. In particular, this disadvantage becomes apparent when the rotational rate of the measuring portion is high. Moreover, this disadvantage may cause an increase in production costs and maintenance costs of the apparatus.